Train-indication system



March 19, 1929. c, wHlTNEY 1,706,013

TRAIN INDICATION SYSTEM Filed July 1, 1925 s Sheets-Sheet 1 ar of/rer Qua-fen.

/NVEN7'UR' March 19, 1929. G. c. WHITNEY 1,706,013

' TRAIN INDICATION SYSTEM Filed July 1, 1925 :s Sheets-Shet 2 guparposadp pa/a/hn car/v02! Normal //'m/' b maica/Ion cur- Marh" l9, 1929. 3. c. WHITNEY TRAIN INDICATION SYSTEM 3 Sheets-Sheet Filed July 1, 1925 i n Pf/M I I I I my current F/ux waw mar/mum UNITED STATES PATENT OFFICE.

GILBERT C. WHITNEY, OF N EW YORK, N. Y.

TRAIN -I'N DICATION SYSTEM.

Application filed July 1,

This invention relates to train describers and train indicators in general wherein means are provided to indicate the position or describe the movement ofa train on a railway track, and in particular, a novel means is disclosed for inexpensively determining conditions affecting the operation of an electrified railway system and also. providing a means of communication between the train, at any time :from any point, and the customary tower or other quarters.

This present application is a continuation, in part, of myco-pending application, Serial 7 No. 33,781, filed May 29, 1925, and my prior PatentNo. 1,596,222, issued August 17, 1926, for train indicationsystem.

The general objects of this invention are; to provide a simple and inxepensive means whereby an indication as to whether an electrically propelled train, using the track rails for return of the propulsion current, is pro- -ceeding under electric motor poweroris coasting; to provide a means of determination as to defective railsor defective bonding in the propulsion return currentsystem; and to incorporate the same into the system of my prior application, Serial No. 33,731, and my prior Patent No. 1,596,222, so that a single simple system will indicate the position of the train; whether the train is moving or at rest and the direct-ion if moving; as to whether the train is being electrically propelled or is coasting; as to the value and main tenance of the propulsion return current-system; as to gen'era-l operating eflicienc-y of the motorinan; to locate all indication receiving apparatus inexpensively at one place or more, if desired, for a given territoi and to provide a means for the motorman to communicate to the tower, despatchefis ofiice or other selected station.

lvly invention, herein disclosed, is identically the same asdisclosed in. my prior Patent No. 1,596,222, hereinbefore referred to, except that additional features inherent to said system, when installed on electrified railroads, are'brought into effect.

In describing my invention 1 will refer to the accompanying drawings wherein F 1 sets forth the indication system of my prior application to which has been added a third rail to conduct the electric power from the power house generator G to the electric no= tored train on the track section; Fig a dose tive harmonic wave drawing sli.\-,1ng the r ations of thepriniai'g ands;

- circuit Fig.

of relay 24-. Relay 24.

; .0 1 sihie bu 1925. Serial NO. 40,789.

currents in the field inductive coupling when only one A. C. current is flowing in the track 3 shows a typical magnetization curve well known in the electrical arts; Fig. 4 is a descriptive harmonic wave drawing showing the relation and influence of the different characteristics of the waveshapes of Fig. 2 when a direct current (propulsion re turn current) of different amounts is superposed on the A. C. indication current; and F 5 is a descriptive wave drawing showing the relation and influence of the different characteristics of the wave shapes of Fig. 2 when an alternating current (propulsion return current) of di'lferent frequency is super posed on the A. C. indication current; all of which figures will be referred to hereinafter.

The reference characters distinguishing the parts of Fig. 1 are the same as in my prior patent, hereinb-efore referred to.

Referring, to Fig. l, a track section is set apart by insulated track rail joints 8the track rails ofthe section being identified by the reference characters 6 and 7. At one end of said track section a transformer 9 is shown connected to track rails 6, 7, by meansof track wires 10, 11, resistance 12 and fuse 13. Transformer 9 is the medium, when energized by means of wires 1-1, 15, from power wires 16, 17, connected to the source of energy alternator 18, by which appropriate current supply, when a train is not present, is trans mitted over track rails 6, 7., to track wires, 19. 20, fuse 21, and resistance 22 to winding 2 is shown deenerized be cause, as illustrated. a train is present in the track section. indiug of relav 24: re-

ceives energy by means of wires 26, 27, from power wires 16, 17, and thus far the whole constitutes-the well-known alternating current track circuit wherein most of the energy required for the operation of the track relay 24 is supplied locally and only a small part or activating current is transmitted over the track rails. Also, in conventionalmanner, I have shown signal controlled by contact 2-8 of track re 2 1 and control wires 29, 30, and 81. The tracl' and circuit and signal and circuit des' 1 outline-cl above is intended simply as a structure and I make no claims of invention in connection therewithit is shown only to provide a basis for suitably illus rating my invention. I have illustrated but one track section for the purpose of the drawing as simple posit. will he antlers. mlthat; inprac 24 passes through said winding 35. Inductively coupled to winding is shown secondarywinding 36 and the current induced therein is carricdover transmission wires 37, 38, to the tower or other selected point and there. energizes winding 40 of transformer (inductive coupling) 39. Inductively cou pled to winding 40 is shown secondary windf ing 41 and the current induced therein becomes available and is used for energizing indicator device lamp 42 or other similarly appropriated means, as will be appreciated. When the track section is notoccupied by a train, winding 23 andresistance 22 are ineludedv in series in the circuit receiving current which passes iroin transt'o 'mer 9 and through winding 35, but when a train enters the track section the wheels of the train, having negligible resistance, shunt out said Y winding and resistance and due thereto more current flows from transformer 9 via winding 35.1 Theincreased rate of current flow varies depending upon the position of said train in the track section, being lowest when the. train is furthest distant from transformer 9, because of the resistance of the 7 track rails 6,7, as will be appreciated. From the above it will be clear, that the current flow in the transmission circuit 37, 38, and

consequently illumination of indicator lamp 42"will be least when said track section isnot occupied and will variably increase with the entrance onto and passage of the train along teward-the transformer 9 end of the track section.

l the ground.

The rails 6 and 7 generally securely mounted on wooden ties to maintain the no er 'au e relation and l P a: o

to serve as an insulating medium to insulate rails 6 and 7 one. from the other and from Because of .the fact that the wooden ties are subjected to rain and other moisture their value as an insulator varies and due thereto it is customary to apply only low voltages for the regular energy supply to the track circuit.

Itis the general custom to arrange the indicatorlamps at acentral point for a given .territory which may be of considerable extent andfowing to the great number-of circuits involved, economy demands that small} Wires be used in the transmission circuit and naturally only a small transmission current can be tolerated, otherwise the loss in transmission would not only be prohibitive but would otherwise interfere with the indication as hereinafter pointed out. Starting then cuit from the track of the track section are with the necessarily low track circuit voltage I provide inductive coupling 34 to act as a step-up transformer to provide a higher transmission circuit voltage and the correspon ding transmission current for indication of 0.015 ampere and purposes is of the order less. Now as is well-known an indication lamp of high voltage'and low wattage (one (1) watt and less) is not commercially possible because of the inability to providea filament which will heat ona current flow of the above mentioned order of 0.015 ampere and less and accordingly I provide receiver inductive coupling transformer 39 or the step-down type and wherein the resultant induced indicating current flow tolamp 42 is of the order of 0.080 to 0.350 ampere and at an operating voltage of from approiriiiiately one (1) volt to five volts. Thus it will be evident that, in the use of transformer 39, means have been provided to effect an indication on a very small transmitted power and with a minimum in the losses of transmission. A minimum in the losses of transmission is important for the reason that the variation in current flow in the rail circuit, as between the train or car at severalpoints within a given track section, is small and all efforts must he made to conserve the results, of the variation, during transmission to the indication device.

I have previously shown that the train enters onto and proceeds over the'track section and it will be understood that the train, represented by car-wheels 43-43, electrically connected by member 44, is equipped with propelling electric motor 45,. a controller 46 for said motor and third rail sliding contact 47 whichcontact is in continuous contact with third rail 48. The propulson current is suppliedby generator G to the third rail 48 by means of wire 49 and the return 011- rails is via wire 50 connected to track rail .7. It will be understood,

that the bonds'connecting 'theiseveral traclr rails comprising track rail 7 of tl'ietrack section are of suitablyheavy design appropriate 'to the purpose. 1 The operation of the train by motor power is simple Controller 46 is moved into engagement with contact 46 and current then flows from generator G via wire 49, third rail 48, third'rail sliding contact '47, thence via controller-46, now closed, motor 45 connecting i'iieinber 44, car-wheels and returning thence over rails 6 and 7 togenerator G via wire 50 and rotation of the motor is produced resulting in movementct the train, as willbe appreciated. The train operating means, just described, form no oart of in T invention exce )t that intermittent manual operation of controller 46 is involved in certain combinations to' produce,

and producing various effects on the indication system by virtue of the current flowing viacontroller 46and excepting also that the propulsion current may at times be can ill) 7 than fraction of the capacity of inductive bined with signaling current to influence the indication system.

I have stated that the return of the propulsion current from the motor is via track rails 6 and 7 and it will be appzrentthat, since track rail 6'is separate from track rail 7, at the generator G end of the track section, all propulsion current flowing in track rail 6 must flow via the secondary circuit of trans former 9 which includes wires 10 and i1, fuse 13 and resistance 12 with winding of my inductive coupling 3% in multiple with resistance 12.

From the foregoing it will be evident that, the return propulsion current actually flows in the circuit win the alternating current from transformer 9 and both currents flow in the winding 35 of inductive coupling and in amounts comparable to the conditions of the circuits at any particular time.

In Fig. 2 I have shown a diagram illustrating a. simple sine wave A of a twenty-five v() cycle alternating currentand representing the current used in the signaling and indication system and is to be understood, for the purposes of clearly describing my invention only, as being the current wave, of maximum Value P, flowing in winding of inductive coupling 84 when the track section is in normal condition and not occupied by a train and when in this condition the induced current, wave B of maximum value Q, flowing in the transmission circuit 37, 38, which includes winding 36, is not sufiicient to produce even a slig t illumination of indicator lamp i2. Induced current wave B is shown in time relation 90 later than-primary current wave A, because of the fact that, as ordinarily designed, the power requirements of my indicating device, lamp 42 or other appropriate means, is small andm no wise more coupling 34 so that the time relation of the induced current wave follows the induced uo load voltage wave, as is well known in the design of induction apparatus but it will be understood that with a non inductive indicating means coupled to inductive coupling 3% and of approximately the capacity thereof the induced current wave would be in approximately the same time relation as primary current wave A. At the bottom of 2 I have shown, in full hatched order the corresponding value of power in the tran mission circuit and consequently the com parative value of induced current flow C to the indicating device lamp 42 when the track section is not occupied. Now, when the train enters the track section, as before explained, and without electric power, the car-wheel l3-43-1 short-circuiting track rails (5 and 7 produces a shunt on transformer 9. causing increased current to flow via winding .35 and for the condition when the car-wheel shunt is at the exit end of the track section the corresponding current waves are shown respective ly AA of value PP and BB of value (3Q and the comparative value-of energy flow to indi cating lamp device e2 at CC. It being understood, of course, that with the car-wheel shunt at intermediate points in the track section the values would be synchronously correspondingly intermediate those just previously described. It will be understood, of course, that the increase in track circuit current flow via. winding 35, when the track section becomes occupied, is reflected in the transmission circuit eventually to appear at the indication device, in accordance with the well-known laws of mutual induction and because of chan e in the flux density in the magnetic circuit which change is wrought by the primary or track circuit current synchronously and automatically.

At thistime I desire to point out that, while, hereinbefore, I have explained that when the track section is not occu ied the energy supply to the lamp 4:2 is not sufi'lcient to produce even a slight illumination, I wish it to be understood distinctly that I may arrange to have the energy flow to the lamp, when the track section is not occupied, sufficient to cause the lamp filament to glow dimly or partially lighted and thereafter with synchronously progressively more illumination as the section becomes occupied and the train proceeds, from left to right, therethrough.

It will be appreciated that track relay 2% is not essential to the operation of my indication system and therefore may be used or omitted as desired.

I have explained that tl e progressive increase in illumination of lamp a2 is a synchronous indication of the movement of the train from left to right. The synchronous indication of a train movement in the opposite direction would he shown by the lamp appearing with full illumination as the carwheel shun enters the section. (from the right) and thereafter with synchronously diminishing value as the car-wheel shunt proceeds through the section.

Resistance 12, shown in multiple with winding 35, in addition to performing the functions; of preventing the train being a short circuit on transformer 9of providing proper phase relation for the operation of relay 2-l-of permitting suhlcient current to flow to the track rails for the regular operation of relay 2-l independent of winding 35, which winding may become highly re ctive due to an accidentally opened secondary circuit which includes winding 36 also serves, as hereinafter set forth, in connection with adjusting the effects and influences due to the return propulsion current heir :uperposed on the original alternz-rting current usedfor the track circuiting and indication system. I also direct attention to the fact that an adjustable resistance (not shown) relays on track circuits of differentlengths and characteristics. I

I have referred to thefact that the variation in track circuit current via winding is reflected in the transmission circuit 3438 synchronously and automatically by virtue of change in magnetic flux density in the magnetic circuit of inductive coupling transformer 34. 'This action will be more readily understood by referring to Fig. 3, wherein is represented what is known as a magnetization 'curve-the-abscissa representing flux density and the ordinates representing current flow in a winding surrounding the magnetic circuit- 7 which shows graphically the comparative be havior of iron when under the influence of an electric current. Referring to F 1g. 3 it will be evident that the greater the current flow the greater the flux density and vice versa with uniform variation but this uniform variation only holds true under the knee K of the curve. Above the knee of the curve, it will be noted, a comparatively great increase 111 current flow will be accompanied by only a small increase in flux density. In general,

inductive coupling 34 is so designed that the current flow in the'primary winding 35, when the track circuit is not occupied, produces only a-low flux -densityconsequently only a low induced power appears in the transmission circuit-and when the car-wheel shunt is at transformer 9 end of the track circuit the increase in current flow in w1nding-35 produces a correspondingly greater flux density (but still under the knee of the'curve) and consequently a greater induced power in the transmission circuit. lhe foregoing, of course, has reference to the operation of 1nductivecoupling 34 and its influence on the indication system when propulsion current is not present in the track circuit to any appreciable degree.

I Referring again to Fig. 3 it will be noted that the magnetization curve indicates uniform variation under the knee of the curve and that a comparatively great increase in magnetizing current thereafter produces only a small change in flux dens1ty-1n fact, as illustrated, an lncrease of 100% in magnetizing current shows only about 30% increase in flux density, and as the induced power 18 due.

to the flux density and notto the magnetizing current it is apparent that variations in magnetization current above the knee of the curve will not be reflected proportionately 1n the transmission circuit and therein lies the basis for the influences and effects of propulsion current flow in winding 35 on the indication system presently to be described.

Referring to Fig. 1, it will be observed that track rail 6 is connected permanently in multiple with track rail 7 at therelay end of the track section and also again at the transformer 9 end of the track section;the multiple at the relay end being via-wires 19, 20,

fuse 21 resistance 22 and winding 23 and at the transformer end via wires 10, 11, fuse 13, secondary winding of transformer 9 and resistance 12 with winding 35 in multiple.

bviously, track rail 6 is not intended-t0 carry any appreciable amount of propulsion current and resistances 12 and 522 are inserted in the respective paths to restrict the flow of propulsion (direct or alternating) current therein because an excessive flow would tend to magnetically saturate the track relay and track transformer 9 and cause heating and other obvious undesirable effects. Owing to the permanent multiple, just explained, some propulsion return currentdoes flow in wind ing 35 at any time a train motor is using power with the track section, illustrated, intervening between said train position and generator G and the train, therefore, need not necessarily be on a particular track section to cause propulsion current to flow via winding 35.

l/Vhen the train enters-the tracksection the train (car-wheels 4l343*) provides a direct connection between rails 6 and 7 of considerably greater conductance than formerly existed and as a consequence track rail 6 is a correspondingly greater conducting path in multiple with track rail 7 and more propulsion return current flows in track rail 6 than formerly. It will be obvious, that the rela tion of track rail 6,'as a conducting vpath in multiple with track rail 7 is variable corresponding to the position (in the track section) of the train, track rail Gbeing of propertionately greater multiple value when the train is at the relay end of the track section and of practically no value when the train is at the transformer 9 end of the track section therefore more propulsion return current flows via winding 35 when the train is at the first mentioned end of the tracksection and variably less of the propulsion current flows via winding 35 as the train proceeds through said track section under electric power.

The effect of direct current (propulsion) flowing with the alternating signaling current in the same circuit is to produce a biasthat is, the direct current which alwaysfiows in the same direction, at a time, may be said to reinforce one-half of the alternating current wave and to suppress the other half of said wave. The actual fact is, that the direct current tends to permanently line up the flux of the magnetic circuitin one direction so that the flux cannot respond to the alternating current signaling current wave and this is illustrated in Fig. l, wherein a direct current (propulsion return current) of the value indicated is assumed. to be in the circuit including winding 35, as herein before explained, and in a direction to suppress the negative half of an alternating current wave. When such is the case, it is apparent that an alternating signaling current of any value present in the same circuit, because of u occupied traclrcircuit, can only influence the flux of the magnetic circuit to the certain extent that the flux is not pre-influenced by the propulsion return current, so to spcalr. To illustrate the conditions in ef feet, a simplesine wave PP ofthe value indiis shown (by dotted line) superposed cated on the direct current component. The flux wave resulting from the combining of the direct current and alternatir a current of these values is showmas identified, andassumes this particular shape because of the fact that propulsion direct currentwill host of the alternating current fiow inwinding does not affect the magnetization appreciably because at that point (at and above the lrnee of the magnetization curve) 'variation in current produces a comparatively small changein flux density. Y

Fig. i is intended to illustrate-at the left end of the figure the proportionable values in eliect with the train, now electrically propelled, entering the left end of the track section and under which condition the alternat in signaling current fiow through winding 3: ould be a minimum (because of the track rail resistance included in the car-wheel shunt on transformer 9) and the propulsion direct current flow through winding 35 would be a na n-inn (because that is the time when the mu 7 iile value of the circuit via track rail 6, transformer 9 and winding 35 in multiple with'track rail 7 is greatest). Fig. 4 at the right end is intended to illustrate the proportionable values in eflect with the train, still electricallypropelled, at the halfway point in'the track circuit. will be appreciated, of course, that, when the train arrives at the transformer 9 end of the track circuit the have practically disappeared and the alternating signaling current will'have become of maximum value in which event the primary current,

the flux wave and the induced current wave will be as described in connection with Fig. 2. It will henoted that the component current due to the propulsion direct current at the left end of Fig. 41 substantially saturates the magnetic circuit up to the knee of the magnetization curve and the further increase of current flow due to the a ternatingsignaling current actsto produce a ripple in the flux wave which ripple follows the A. C. wave in far as the flux density permits and theflux are is shown following only the lower end i BB at first, but, as the propulsion nt component decreases (due to J ceeding through the track cirk adi in: following more and more the wave shaoe f the .alternat ngsignaling current until the flux follows the complete signaling current wave when the train is at the transformer 9 end of the traclrcircuit.

As above explained will be clear that the combination of the direct propulsion current and alternating signaling current in winding 35 acts to produce a unidirectional ripple ef feet on the flux wave of transformer 3-1 with maximum and minimum values in time relation corresponding to the period of the alternating current.

With a variable flux wave, generated according to propulsion direct current and alternating signaling current conditions in the track circuit, a basis is provided to generate a characteristic secondary current flow and wave BB Fig. l illustrates the wave shape of secondary current flow in the transmission circuit 3'Z-.88.

Referring to Fig. l, it will be observed that the secondary current wave BB is shown to have 0 value at point B from which point the wave with a concave wave front indicates an increase in current flow to a certain posiive value S corresponding to the density and rate of change of the flux at that timefrom which point the secondary current value (wave BB) recedes rapidly with a straight wave back to 0 value and rebuilds with a straight wave front to a certain *alue S corresponding to the density and rate of change of the flux as before and then said secondary current value recedes with a concave wave back to 0 value at point R and thereafter similarly with recurring cycles. That the positive wave front should be so shaped will be evident from the fact that at point R the flux, though at a maximum value, is at rest and as the cycle proceeds the value of flux is reduced at an increasing rate until the point S (Wave BB) is reached. of change then slows up rapidly thus accounting for the straight positive back of wave BB and as the flux wave rate of change comparatively rapidly increases until a point on the flux wave corresponding to point S (wave BB) is reached it will be clear that the negative front of wave BB will be straight. Now, even though the value of flux is increasing, the rate of change is slower thus accounting for the concave negative baclrof wave BB.

As the value of the propulsion direct current component is decreased (as the train proceeds through the track circuit) the flux wave follows the alternating signaling current wave for a greater part of a cycle resulting in the positivewave fronts and negative wave backs of wave BB still concave but with a greater amplitude and with the positive Wave backs and negative wave fronts of wave BB gradually assuming a convex iorm as is clearly indicated in the shape-of wave BB at is right end of Fig. It will be appreciated, of course, that as the direct current com- The flux wave rate plitude of I current the longer the dark interval so that the flicker indication the illumination be accepted asa conupararive indexas ponent is reduced (due to the train reaching the transformer 9 end of the track circuit) the concave positive wave front and negative wave back will be replaced by the regular sine wave shape and to all intents and purposes wave BB, of Fig. 4: will become a facsimile of wave BB of Fig. 2.

In the above description it was assumed that the propulsion direct current flow in winding 35 was such as to reinforce the positive half of the alternating signaling current wave and in this event the secondary wave BB positive fronts and negative backs were suppressed but it will be appreciated that the propulsiondirect'current flow, according to design, or the conditions of operation, may

be used to reinforce the ne ative half of the alternating signaling current wave in which event the secondary wave BB negative fronts andpositive backs would bes'uppressed.

Referring now to the'power waveCC Fig.

ethe corresponding points of which are line referenced to the flux wave and the induced current wave: BB. It will be noted that, be-- cause of the direct current component of the current flow "inwinding 35," comparatively little influence of the alternating current component is reflected in the transmission circuit andvwith very little semblanceof sine wave shape. ference in fronts and backs of the induced current wave BB. Asbetween points R and R (wave BB) of recurring cycles, the periodicity of'the alternating signaling current (forthis case 1/25 second) is maintained and the influence of the signaling current reflected is fractionally that of the negative half of the alternating current primary wave (when the train is entering the track section) and the power wave peaks (wave CC) occur midwaybetween points in the power wave CC'corresponding to points R and R of induced current wave BB. The lower the ani-v the power wave CC the closer the power wavepeaks or agiven cycle appear together and the closer the power wave peaks of a given cycle occur the longer must be the period between the power waves of recurring cycles, all of which is clearly set forth in Thelong periods as between power waves of recurring cycles are essentially periodsof substantially no power flow in the transmission circuit and hence no power input to the indicating device-in this case lamp 42. This gives rise to a flicker condition of the illumination of lamp 42, the lightand dark intervals of 'which vary according to the" 7 practice I have,-at times, arranged the design amount of Jropulsion direct current flow in winding 35"the greater the amount of direct may - value ofthe: direct current flow in'win'ding 35,-it being understood, that dii ferent pro- This is so because of the difportions of direct current, and alternating current will act responslvely in amanner WlllGh can readily be set forth in lllustration and in practice as hereinbefore explained,

having in mind, of course, that the greater the alternating current value the sharper the peaks with agiven direct'current component. I desire it to be understood that I have, at times, arranged the design of the inductive coupling 34 so that with the presence of a suitable amount of direct current flow 1n winding 35 the induced effects of the original sion current is present when thetrain enters the track section the indication device will not inductively respond to whatever indication current is flowing in thetrack circuit because of saturation ofinductive coupling 34 by the propulsion current; annulled and nullify-meaning that Whilethe indication device may be responding to indication current the appearance of an excess amount of propulsion current will act to cancel said indication effect. I I

The lamp indicator in being operative to differentiate, by uneven periods of illumination, ashereinbefore pointed out, is, therefore, a device responsively and sensitively operativeon an unsymmetrical wave form. Attention is directedto the fact that, in the description in connection vwith Fig. 2, it was explained that current wave A whenthe track circuit was not'occupie d did not induce a sufficient amount of current wave B (Fig. 2), in the circuit including winding 36 to even slightly illuminate lamp indicator 42 and that an increase in alternating current flow in primary winging 35,doesprovide increased induced current flows in the transmission circuit 7 and consequently increased illumination of lamp 42; f This, of course, is due to the increase in fluxdensity whicl1,-with the cyclic frequency remaining unchanged, produces" a more rapid rate of flux change, which, as iswell understood in the art, accounts for the mduced power in the secondary circuit. As is well understood induction ma be carried into effect a 7 a e a b anincrease 1n the flux dens t i of the XIl1P-' 'netic circuit, by increasing the cyclic frelit (prone) per unit of time or both and in occupiedtrack section) Qin'winding 35 into a rippledirectcurrentthemaxiinum and minimum values of which correspond to the positive and negative maximum values of the original alternating current and thus generating a flux wave similarly as set forth in Fig. 4c, in fact it is apparent that an actual decrease 'in alternating current flow in Winding (with the track circuit unoccupied) can take place and when reinforced by a suitable value of superposed direct current, an induced current wave BB (Fig. 4) would beproduced which would possess the necessary produce responsive synchronous illumination of indicator lamp 42. This gives rise to the fact, that the indication device may act without any increase in the energy supply from transformer 9all of which is due to the fact of the degree of magnetization of the magnetic circuit of inductive coupling 34 being changed by virtue of the propulsion return current flow.

It has been explained, that the track rails are permanently connected in multiple, for the case illustrated, and therefore bear a cer tam shunt relation to each other. 'ivov-x, if said relation becomes-disturbed, by virtue of defective bonding-or cracked rail, the fact I will be exhibited by the indicator device as flow through motor as ried circuit controller 46, as will follows: If the defect occurs in track rail fa an additional proportion of propulsion return current flows viawinding and if the defect is in track rail 6 less than the normal amount of propulsion current flows via winding 35 and in addition the former characteristic value of car-wheel shunt variation would be altered both of which produce correspondingly different effects in the indication system, all as hereinbefore pointed out, due to change in degree of magnetization of the iron core of inductive coupling 34.

I have explained that the circuit for the propulsion return current from motor L5 was via track rails 6 and 7 and that a portion of the return current flowed via winding 35. N ow, in order that propulsion current may and via winding 85, operating circuit controller 46 m ust'be closed and since this controller, either directly or by means of master controller as is well known in the art, may be opera-red at will by tl 'e motorman and thus bring about a change in the amount and duration of propulsion current flow in winding 35, and consequently in the induced current effects on the indicator device, it is readily apparent, that I have provided a system whereby the motorman without removing his hand from the controller, without stopping the train, and from any point in the track section, may communicate with the tower or other selected location of the indicator device, said communication be ing originated by the opening and closing of the motor operating circuit at the train car be appreciated' The several indications of lamp 42, for the case of the lamp dark with the track section unoccupied, are as follows;

1. Section unoccupied11o illumination.

2. Train entering sectioncoasting-illumination of low value and steady character.

3. Train continues through sectioncoasting-increasing value of illun'iination of steady character and synchronous with train movement.

4. Train stops-the value of illumination synchronously attained remains unchanged.

5. Train moves in opposite direction coasting-the indications 1 to 4 appear in reverse order. That is, the lamp begins full illumination with the train entering the track section.

6. Train entering section under D. C. electric motor powerillumination of low value but flicker" 1g character.

7. Train continues through section under D. C. electric motor powerincreased value illumination of flickering character-the flicker gradually disappearing and the indication as in 3 gradually appearing.

8. Train starts coasting in scctionflicl er disappearsthereaf'ter as in 3.

9. Train coasting begins D. C. motor power operationfirst indication as in 3 and thereafter as in 7. w

10. Motorman communicating with despatchera series of flicker and steady illumination accordin to prearranged code.

-Theflickering indications are of several values and characteristics according to the cycle of light and dark intervals ;-that is, with a given cycle 1/10 of which is light and 9/10 dark a characteristic impression is formed which is materially different from a cycle 5/10 of which is light and 5/10 dark and in this manner COHlPiUTtItlVG values of super posed direct current flow are readily discer ible. In other words, the flicker is slow or fast. So also, given an alternating current wave the larger the current value the sharper the wave at its maximum point and the smaller the current value the flatter the wave at its maximum point with correspondingly different effects in combination with the directcurrent component, as will be evident by referring to the flux wave of Fig. 4.

vVhen installed on railroads using direct current for propulsion purposes I prefer to use a frequency of alternating current not in excess of 60 cycles per second because the filament section of the lamp required to respond to power flow for light and dark intervals becomes too frail, but I desire it to be understood that wheninstalled on railroads using alternating current for propulsion purposes a much higher frequency is perfectly feasible because of the node or beat frequency effect due to superposing an alternating current of one frequency on an alternating current of a difierent frequency, as will presently be pointed, out.

Referring to 1 have shown a simplesine wave identified as cycle propulsion current 'and intended to illustrate the propulsion current flow (when a train is 1nov-' ing under A. G. electric motor power) in winding or" my system (when installed on A. G. electrified railroads using 25 cycle A. C. for propulsion purposes) under conditions I previously explained for the case with D. C.

tion-system alternating current flow l/Vave AA represents the indica- (in this case cycles) in winding with the track section occupied. As'illustrated the 25 cycle propulsion current is twice the value of the propulsion.

.60 cycle signal current and the influence of the two waves combined (identified as pri-, 'mary current) inductive coupling an) tending to follow the is to produce a flux wave (in 25 c cle oeriodicit but with harmonics due to the 60 cycle periodicity. However, owing to the saturation of inductive coupling 3%,

as 'hereinbefore explained, the peak points of the combined primary current values are suppressed, on account-oi the flux density,

' and the secondary voltage wave (indicated) H V follows a shape of greatly different char-' acter than the primary current. This 18 so,

' 'nent has operated to increase therate of change in the flux and at other points. the

because at some points the 60 cycle compoprimary current is not reflected because of saturation oi": the-magnetic circuit of inductive coupling 34l.- V v At the bottom of Fig. 5, Ihave indicated the 25 cycle propulsion current component (above referred to) by dotted lineand by.

the hatched area I have clearly shown the. beats which arethe natural result of the sharp wave rronts and backs which are carried into in character the indication system and lamp 4E2 will synchronously indicate train" presence and movement without 60 cycle current flow in winding 35 -but with reverseetiectthat is, the train in moving from left to right will cause a reduction in indication lamp 4L2 illumination.

I The indications of the i dication lamp 42,

I when installed on A. C. electrified"railroads are substant ally similar to those, as above set forth for D. C. electrified, railroads, except that, ofcourse, 1st, the beat flicker would be substituted for :thefiicker due to tlieD. 2nd, an additional indication v co'mponent,and

in the :form of a comparativelyslow but uniflicker (due to the 25 cycle propulsion form current alone) is developed. These, different types of flickers are brought, about in the use of a comparatively thin'indication lamp filament.

In the specific illustrations and descripl tions herein, I have made use of simple sine waves, b ut it will be understood that my in: vention is broadly adaptable for use and etiective without regard to wave shape andl desire it to be understood that, while I have illustrated and described the indication elf tects as appearing inthe transmission circuit, it will be evident that whatever induced effects are produced in the transmission cir cuit will all be substantially carried through tothe indicationlamp device 42, or other ap' propriate means. a

At th's time it is to be noted, that the alter nating current of the indication system is substantially a carrier wave by 7 means of which a class of information is transmitted to the indication receiver device, either in 'inodified or unmodified wave iormthe modifications being due to thesuperposing of other currents, the eii'ect of which is to produce unsymmetrical wave'shapes.

it is SPGGlilCtlllY ClISClOSBCl, here n, that the flow of propulsion return current, in the sectionalized track rail under the several conditions 18 responsible for the operation of my invention but it is also pointed out that the presence or all currentsin suitable amounts will be indicated in my system, and I further desire itto beunderstood that my invention is not limited to the particular type of track circuit shown,as I have produced similar results with all types of alternating current track circuits, on electrified railroads, includ ing those disclosed in my prior Patent No. 7

1,596,222 and my prior-application Serial'No. 33,731, with the obvious appropriate changes which *any person ordinarily, skilled in the art would use to modify my invention, herein disclosed, and, therefore, Iwishit'to be 1111- v dei'stood that my d sclosure hereinis merely illustrativeand does notexhaust the various embodiments which, come very 'clearlygand broadly withinithe spirit and scope of this in; VBIliJlOIL Having thus described'my invention, 1'

claim and desire to secure by Letters Patent: 1.- A train indication system, characterized by an indicating device responsive to signaling current-and influencedby a current other than said signaling current, both currents flowing in the "rails of a railway track, both currents coacting to indicate the presence and. movement of anelectrically propelled train on said railway track. 7 p

2. A train ind'catioii system including a track circuit and source of signal current,

characterized-by an indicatingdevice responsive to signaling current and 'infiuencedby a current other than said signaling current,

bothcurrents flowing .in one of therails of a railway track, sald device adapted to comparatively indicate variable amounts ofsaid other current.

3. A train'indication system including a track circuit and source of signal current,

characterizedby an indicatingdevice,responsive to a wave-of signaling currentand in sive to signaling currentandinfluencedby a current other than said isignaling current, both currentsflowin in the rails of a railway track, said other currentmodifying the wave form 01 said signalingcurrent.

5. A train indication system including a track circuit and source of signal current,

characterized by an indicating device responsive to signaling current and influenced by a current other than said signaling current, both currentsfiowing in the rails of a railway track, said other current modifying said signaling current 'to produce :an unsymmetrical wave form of current.

6. A train indication system including a track circuit and source of signal current, characterized by an indicatlng device responsiveto signaling current and influenced by a return current otherthan saidsignaling current, both currents flowing in the rails of a railway track, said other current modifying said signaling currenttoproduce an unsymmetrical .wave form, said device sensitive to said unsymmetrical wave form. A

7. A train indication system including a track circuit and source of signal current, characterized by an indicating device responsive to signaling current and influenced by a current other than said signaling current, both currents flowing 1n the rails of a railway track, said-other current modifying said signaling current to produce a characteristic current, said device sensitive 'to said characteristic current. V

8. A train indication system including a track circuit and source of signal current, characterized by an indicating device responsive to signaling current and influenced by a current other than said signaling current, both currents flowing in the rails of a railway track, said other current modifying said signaling current to inductively produce a characteristic Wave, said device synchronously sensitive to said characteristic wave.

9. A train indication system including. a

track circuit and source of signal current,

characterized'by an indicating device responsive to-signalingcurrent and influenced by a current other than said signaling current,

said signaling current controlling said device,

and an excess of said other current nullifying said control.

10. A train indication system including a track circuit and source of signal current, characterized by an indicating device responsive to signaling current and influenced by a return current other thansaid signaling current, an excess of said other current acting to suppress the response of said device to said signaling current.

11. A train indication system including a track circuit and source of signal current, characterized by an indicating device responsive to signaling currentand influenced by a return current-other than said signaling current, both currents controlled by train movement on a railway track, said signaling current ccntrollingsaid device, and an excess of said other current nullifying the response of said device to said signaling current.

12. A train indication system including a track circuit and source of signal current, characterized by an indicating device responsive to signaling current and influenced by current other than said signaling current, both currentscontrolled by train movement on a railway track, said signalingcurrent controlling said device, and an excess of said other current acting to'suppress the :response of said device to said signaling current.

13 A train indication system including a track circuit and source of signal current, characterized by an indicating device responsive to signaling current and influenced by a return current other than said signaling current, both currents controlled by train movement at any point on a railway track, said signaling current controlling said device, and an excess of said other current acting to nullity the response of said device to said signaling current.

14. A train indication system including a track circuit and source of signal current, characterized by an indicating device responsive to signaling current and influenced by a return current other than said signalingcurrent, both currentscontrolled by train movement at any point on a railway track, said signaling current controlling said device, and an excess of said other current acting to suppress the response of said device to said signaling current. a

15. A train indication system including a track circuit and source of signal current, characterized by an indication device responsive to signaling current and influenced by a current other than said signaling current, both currents controlled by train movement at any point on a railway track, the combination ofsaid currents acting to inductively pro duce a current of unsymmetrical phase relation,-said device sensitive to said induced current.

16. A train indication system including a track circuitand source of signal current,

'-:-cli'aracterized by an indicating device'i'espon sive to si 'nalin current and influenced b a current other than said signaling current,

both curi'ents controlled by train movement atany' point on a. railway track, said other current-also controlled by operable train carried means, said device sensitive to the opera- 'tion of said means.

17; A train indication system including a track circuit and source of signal current, characterized by an indication device responsive 'to signaling current and influenced by current other than Sitlfl signaling current,

both currents controlled by trainmovement at anypo nt on a railway track, said other current also controlled by operable train carried 1 means, said means in combination with said other current actingvto iiullify the response of said device to said signaling current.

18. A train indication system including a track circuitand source of s gnal current,

characterized by an indication device respon- "sive to signaling current and influenced by current other than said signaling current, both currents controlled by train movement at any point on a railway track, said other current also controlled by operable train car- 'ried' means, said means'in combination with said other currentacting to suppress the response of'said device to said signaling current. 1 V

19. A train indication system including a track circuit and sourceof signal current, characterized byan indication device respon- 'sive to signaling current'aiid influenced by current other than said signaling current,

both currents controlled by traininovement at any point on a railway track, said other current also controlled by operable train carried means, said means in combination with said other current acting to synchronously influence said indication device.

20. The invention set forth in claim 2, distinguishedby an inductive coupling included in the circuit which includes the track rails, 21. The invention set forth in claim 5', distinguished by an inductive coupling in multiple with a resistance and included in the circuit which includes the track rails.

22. Th'einvention set forth in claim 6. distinguished by-said device being inductively coupled to the circuit in which both said'sign'aling and return currents flow. v

25. The invention set forth in claim 10, distinguished by said device being induc- I tively coupled 'to the circuitin which both 1 distinguished by said device being induc- 'tively'coupled to the circuit in which both said signalingand returncnrrents.flow.

"24;. The invention set forth in claim 11, distinguishedby said device'being inductively coupled to the circuit in which both said signaling and return currents flow. I

. 25 The invention set forth in claim 13,

said signaling and return currents flow,

'26; The invention set forth in laim 14,- distinguished by said .device beingfiiiductively coupled to the circuit in which both said signaling and return currents flow.

27. The invention set forth in claim 16, distinguished by said devicebeinginductively coupled to the circuit in which both said si naling and said othercurrents flow and con trolled-by the train carried means. i

28. The inventionset forth in claim 17, distinguished by "said device being inductively coupled to the circuit in wliichboth said signaling andsaid other currents flow and controlled by the train carried means. 7 V

29. The invention set forth in claim 18, distinguished bysaiddevice being inductively coupled to the circuit in which both said signaling and said other currents flow and controlled by the train carried means.

30. In a-railway tratfic controlling system, a track and circuit adapted for the'operation of electrically propelled trains, a source of energy therefor, a train-including con troller adapted to receive and utilize said energy, another source of energy impressed on the track rails, an inductive coupling adapted to beinfluenced by both sources of energy, and an indication device responsive sponsive to current flow from the second source and sensitive to the operationof the controller. 7 V V 34. The invention set forth in claim 80, with the indication device operative to detect defects'inthe propulsion return current system.

7 35. The invention set forth in claim. 30, with'the indication device operative to detect energy fiow in'the propulsion currentsystem llO independent of increase inthe flow of energy 7 from the second source.

36. The invention set f'OItltlIiGlEtiHi so,

with an electric lamp acting as the indication device and operative to characteristically iiidicate variat ons -1n the energy flow from either of said sources The invention set forth in claim 30, with an electric lamp actingasthe indication device and operative to characteristically indicatevariations in the energy flow through one. of thetra'ck rails from the second source 'andvarious combinations of energy flow from both sources.

38. The invention set fortli' in claim 30,

with an electric lamp acting as the indication device and operative to indicatewhen said train is being operated by energy from the 7 rent system and a car carried circuit controller therefor, said indicatingvdevice responsive to said alternating current flow in said track circuit due to a car thereon, and means including said propulsion current said car and said circuit controller for suppressing the response of said device to said alternating current track circuit current flow.

4C1. In a train controlled railway signal system,a track circuit including a source of alternating current energy, an indicating device incorporated'in said track circuit, an electrically propelled car, a propulsion current system and a car carri d circuit controllertherefor, said indicating device responsive to saidalternating current flow in said track circuit due to a car thereon,and means including said propulsion current said car and said circuit controller acting attnnes to nullify the response of said device to said alternating current track circuit current flow. 7

42. In a train controlled railway signal sys tem, a track circuit including asource of alternating current energy, an indicating device incorporated in said track circuit, an electrically-propelled car, a propulsion current system and a car carried circuit controller therefor, said'indicating device inoperative 'to alternating current flow alone in said track circuit, and means including said propulsion current said car and said circuit controller for increasing the current flow to said device.

13. 'Inia train controlled railway signal system, a track circuit including asource of. alternating current energy, an indicating device connected in series in the energy supply to said track circuit, an electrically propelled car. a propulsion current system and a car carried circuit Controller therefor, said indicating deviceresponsive co-alternating current flow in said track circuit due to a car thereon, and means including said propulsion current said car and said circuit controller for characteristically influencing the response of said device to said alternating current track circuit current flow.

44. In a. train controlled railway signal system, a track section, a track circuit including both rails of said track section, a source of energy including the secondary winding of a transformer for supplying current to said track circuit, anindicating device connectedin sionicurrent to said motor, and a series with the energy supply=to Saidtrackcircuit and cont-rolled by car wheels on said track section, a car equipped with an eletric motor LfOl propelling said car, a source of propulsion a transmission circuit includlng a current, third railsliding contact and the track ails of said 'track circuit for supplying said propulcar-carried controller :for controlling said transmission circuit, said indicating device responsive to saidtrack circuit current alone and to a predetermined amount of propulsion current in combination with said track circuit current but non-.responsive-to a greater amount of said propulsion current.

'45. In a train controlled railway signal system, a track circuit mcludmga source of alternating current supply connected to one end-of said track circuit, an indicating device connectedin series with and responsive to said current supply to said-track circuit and adaptedto be controlledby a car on said track circuit, a car equipped with an electric propelling motor for propelling saidcar, a source of propulsion current, a transmission circuit in cluding a third rail a sliding contact and the track rails of-said track circuit for supplying said propulsion current .to said motor, and a car-carried circuit controller for controlling the current flow in said transmission circuit,

said circuit controller in combination with said propulsion current also acting to influence the control of said indicating device by said car on said track circuit.

46. Ina-railway train indicating system, a source of propulsion current,.a transmission circuitcomprised of a third rail and track rail ireturnsystem, a train including an electric motor adapted to propel said train, said train at times:receivingpropulsion current through said transmission circuit, a car-carried con- 'troller forcontrolling the propulsion current flow'in saidtransmission circuit, an alternating current track circuit including said track railand having a transformer sonice of energy at one end of said track circuit, a primary winding of a second transformer connected inseries with the energy supply to said track circuit, a primary winding of a third trans former connected to the secondary of the second transformer, and an indicating lamp connected to the secondary of the third transformer.

47. The invention set forth in claim 46 with a track relay connected to the track rails at the opposite end of the track circuit, said track relay controlling a block signal system.

48. The method of controlling alternating current signal circuits on an electrically propelled railway system using the track rails for the propulsion return current associated with an alternating current-signaling system which consists in causing a part of the propulsion return current to flow throughthe track rails in common with the signal current when the track section is occupied by acar; and causing an excess of said propulsion return current Ito-act tosuppress the normal response of a signal device to said signal current, substantially as described. '1 l 4E9. T he method of controlling alternating min-cut signal circuits, on an electrically pro- }pellea railway system using the track rails for the propulsion return current associated .tially, as described.

with an alternating current signaling system;

1whichconsists in causing a part of the pro- ;pulsion return current to flow through the track rails in common with the signal current when the'track section is occupied by acar; and causing an excess of said propulsion current to act to nullify the normal response of a signal device to said signal current, substantially as described.

' 50. The niethodof controlling alternating current signal-circuits, on an electrically propelled railway systemusing the track rails for the propulsionreturn current associated with an alternating current signaling system;

' which consists in causing a part of the propulsion return current to How through the track rails incommon with the signal current; and

' causing an increase of said propulsion curi-ent to'act to increase the flow of alternating ci'irrent energy to a signal device, substan- 51. TlIQ'IDGtlIOCl of controlling alternating current signal c rcuits, on an electrically propelledrailway'system using the track rails for the propulsion return current associated with an alternating current signaling system;

which consists in causing a part of the proiulsion current to flow through the track rails in common with the signal current when r the track section is occupied by an electrically propelled car; and causing the combination of propulsion return current and signal cur ,rent to synchronously operate an indicating device to show when, a'car is being electrically propelled, substantially as described.

52. The method of controlling'alternating current signal circuits, on an electricallyprope'lled railway system using thetrack rails for thepropulsion return current associated with an alternating current signaling system; which consists in causing a part of the propelling current to flow in a circuit with said signaling current when the tracksection is occupied by a car; and causing said propelling current to niodii y'the signaling current to produce a characteristic pulsating current; for operating a signaldevice sensitive to said alternating current and sensitive to said pulsating current.

The methodofindicating the movement of anelectrically propelled train onaraiL way track, associated with an alternating current signaling system; which consists in arising a part of the propulsion return current to flow in a circuit with said signaling current and causing said propulsion return current to produce a pulsating current pro portional to the positioiioi' the train on said track, for synchronously operatingan incli- Vcating dGVlCGJ 54. In a railway traific controlling system, a track circuit including a source of energy,

an indication transmitter included in the energy supply to said track C1ICL11l3,ilI1 additional sourceoif energy at times flowing in said track circuit, said transmitter responsive to the current flowirom both sources in'said track circuit, and an indication receiver device synchronously responsive to induced current flow from said transmitter and sensitive to indicate the presence of either or both sources ofenergy in the track circuit.

55..The invention set lorth in claim 54,

said indication device inductively coupled to said transmitter. I, I

7 56. The invention set forth in claini5al, said indication dev ce inductively coupled to said transmitter,- SfllCl device synchronously responsive to beat frequency current flow in the transmitter; I V

57. The invention set foith'in claim 54,

. said indicationdevice inductively coupled to rent flow from either or both ot said sources.

' Signed at Brooklyn, in the county of Kings and State of New York, this 30th day of June,

'' eiLBnnT o. WHITNEY. 

